This invention generally relates to navigation or route guidance systems and, more particularly, to a graphical user interface having improved access to multiple information screens for a route guidance system.
Navigation systems generally provide a recommended route from a starting point to a desired destination. Generally, the starting point and desired destination are selected from a large database of roads stored in a mass media storage, such as a CD ROM, which includes the roads in the area to be traveled by the user. The navigation system can be located in a personal computer or it can be installed in a vehicle. If the navigation system is installed in a vehicle, the starting point is typically the current position of the vehicle, which can be input to the navigation system by an associated position determining system that usually includes a GPS (Global Positioning System) receiver.
The navigation system determines a route from the starting point to the destination utilizing an algorithm well known to those in the art and currently in use in many navigation systems. Usually there are many potential routes between the selected starting point and the desired destination. Typical navigation systems select a recommended route based upon certain "cost" values associated with each segment of road in the road database. These cost values include the length of the road segment and the estimated time of travel through the road segment. The navigation system selects the potential route with the lowest total cost to be the recommended route. Depending upon the predetermined algorithm of the navigation system, the navigation system will recommend the route with the shortest total length, the lowest total time, or some weighted average of length and time.
The recommended route is then displayed to the user as a map showing the starting point and desired destination and highlighting the recommended route. Preferably, if the navigation system is installed in a vehicle, the navigation system displays the current position of the vehicle and provides turn-by-turn instructions to the driver, guiding the driver to the selected destination.
Navigation systems typically include a graphical user interface that allows a user to input the desired destination. For example, the user must input a city name for the desired destination. Since a full keyboard is impractical in a vehicle, the typical graphical user interface includes a directional input device such as a four-way button. The user is presented with the letters of the alphabet arranged in a single large rectangular array. The typical system requires the user to scroll through the alphabet one letter at a time using the directional input device, selecting a desired letter when it becomes highlighted. These systems have the disadvantage of requiring a large number of key strokes to input a given letter and the city name. Such systems can also be very time consuming and frustrating for a user. Further, with the viewable area limited by the screen size, the displayed characters are commonly limited to only those that are essential.
Thus, it is desirable to provide a graphical user interface and a method that permits a user to rapidly select one character from a large array of characters using a simple input device. It is furthermore desirable to provide a graphical user interface that allows access to any number of characters without increasing the display size and with only a minimal number of keystrokes.